gstreamer/gst/gstelementfactory.c

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/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
* 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
*
* gstelementfactory.c: GstElementFactory object, support routines
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "gst_private.h"
#include "gstelement.h"
#include "gstregistrypool.h"
#include "gstinfo.h"
GST_DEBUG_CATEGORY_STATIC (element_factory_debug);
#define GST_CAT_DEFAULT element_factory_debug
static void gst_element_factory_class_init (GstElementFactoryClass *klass);
static void gst_element_factory_init (GstElementFactory *factory);
static void gst_element_factory_unload_thyself (GstPluginFeature *feature);
static GstPluginFeatureClass *parent_class = NULL;
/* static guint gst_element_factory_signals[LAST_SIGNAL] = { 0 }; */
GType
gst_element_factory_get_type (void)
{
static GType elementfactory_type = 0;
if (!elementfactory_type) {
static const GTypeInfo elementfactory_info = {
sizeof (GstElementFactoryClass),
NULL,
NULL,
(GClassInitFunc) gst_element_factory_class_init,
NULL,
NULL,
sizeof(GstElementFactory),
0,
(GInstanceInitFunc) gst_element_factory_init,
NULL
};
elementfactory_type = g_type_register_static (GST_TYPE_PLUGIN_FEATURE,
"GstElementFactory", &elementfactory_info, 0);
GST_DEBUG_CATEGORY_INIT (element_factory_debug, "GST_ELEMENT_FACTORY",
GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED,
"element factories keep information about installed elements");
}
return elementfactory_type;
}
static void
gst_element_factory_class_init (GstElementFactoryClass *klass)
{
GObjectClass *gobject_class;
GstObjectClass *gstobject_class;
GstPluginFeatureClass *gstpluginfeature_class;
gobject_class = (GObjectClass*)klass;
gstobject_class = (GstObjectClass*)klass;
gstpluginfeature_class = (GstPluginFeatureClass*) klass;
parent_class = g_type_class_peek_parent (klass);
gstpluginfeature_class->unload_thyself = GST_DEBUG_FUNCPTR (gst_element_factory_unload_thyself);
}
static void
gst_element_factory_init (GstElementFactory *factory)
{
factory->padtemplates = NULL;
factory->numpadtemplates = 0;
}
/**
* gst_element_factory_find:
* @name: name of factory to find
*
* Search for an element factory of the given name.
*
* Returns: #GstElementFactory if found, NULL otherwise
*/
GstElementFactory*
gst_element_factory_find (const gchar *name)
{
GstPluginFeature *feature;
g_return_val_if_fail(name != NULL, NULL);
feature = gst_registry_pool_find_feature (name, GST_TYPE_ELEMENT_FACTORY);
if (feature)
return GST_ELEMENT_FACTORY (feature);
/* this should be an ERROR */
GST_DEBUG ("no such elementfactory \"%s\"", name);
return NULL;
}
void
__gst_element_details_clear (GstElementDetails *dp)
{
g_free (dp->longname);
dp->longname = NULL;
g_free (dp->klass);
dp->klass = NULL;
g_free (dp->description);
dp->description = NULL;
g_free (dp->author);
dp->author = NULL;
}
void
__gst_element_details_set (GstElementDetails *dest, const GstElementDetails *src)
{
dest->longname = g_strdup (src->longname);
dest->klass = g_strdup (src->klass);
dest->description = g_strdup (src->description);
dest->author = g_strdup (src->author);
}
void
__gst_element_details_copy (GstElementDetails *dest, const GstElementDetails *src)
{
__gst_element_details_clear (dest);
__gst_element_details_set (dest, src);
}
static void
gst_element_factory_cleanup (GstElementFactory *factory)
{
__gst_element_details_clear (&factory->details);
if (factory->type) {
g_type_class_unref (g_type_class_peek (factory->type));
factory->type = 0;
}
g_list_foreach (factory->padtemplates, (GFunc) g_object_unref, NULL);
g_list_free (factory->padtemplates);
factory->padtemplates = NULL;
factory->numpadtemplates = 0;
}
/**
* gst_element_register:
* @plugin:
* @name: name of elements of this type
* @rank: rank of element (higher rank means more importance when autoplugging)
* @type: GType of element to register
*
* Create a new elementfactory capable of insantiating objects of the
* given type.
*
* Returns: TRUE, if the registering succeeded, FALSE on error
*/
gboolean
gst_element_register (GstPlugin *plugin, const gchar *name, guint rank, GType type)
{
GstElementFactory *factory;
GstElementClass *klass;
g_return_val_if_fail (name != NULL, FALSE);
g_return_val_if_fail (g_type_is_a (type, GST_TYPE_ELEMENT), FALSE);
factory = gst_element_factory_find (name);
if (!factory) {
klass = GST_ELEMENT_CLASS (g_type_class_ref (type));
factory = GST_ELEMENT_FACTORY (g_object_new (GST_TYPE_ELEMENT_FACTORY, NULL));
gst_plugin_feature_set_name (GST_PLUGIN_FEATURE (factory), name);
GST_LOG_OBJECT (factory, "Created new elementfactory for type %s", g_type_name (type));
} else {
g_return_val_if_fail (factory->type == 0, FALSE);
klass = GST_ELEMENT_CLASS (g_type_class_ref (type));
gst_element_factory_cleanup (factory);
GST_LOG_OBJECT (factory, "Reuse existing elementfactory for type %s", g_type_name (type));
}
factory->type = type;
__gst_element_details_copy (&factory->details, &klass->details);
factory->padtemplates = g_list_copy (klass->padtemplates);
g_list_foreach (factory->padtemplates, (GFunc) g_object_ref, NULL);
factory->numpadtemplates = klass->numpadtemplates;
gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE (factory), rank);
gst_plugin_add_feature (plugin, GST_PLUGIN_FEATURE (factory));
return TRUE;
}
/**
* gst_element_factory_create:
* @factory: factory to instantiate
* @name: name of new element
*
* Create a new element of the type defined by the given elementfactory.
* It will be given the name supplied, since all elements require a name as
* their first argument.
*
* Returns: new #GstElement or NULL if the element couldn't be created
*/
GstElement*
gst_element_factory_create (GstElementFactory *factory,
const gchar *name)
{
GstElement *element;
GstElementClass *oclass;
g_return_val_if_fail (factory != NULL, NULL);
if (!gst_plugin_feature_ensure_loaded (GST_PLUGIN_FEATURE (factory))) {
GST_INFO ("could not load element factory for element \"%s\"", name);
return NULL;
}
GST_LOG_OBJECT (factory, "creating element (name \"%s\", type %d)",
GST_STR_NULL (name), (gint) factory->type);
if (factory->type == 0) {
g_critical ("Factory for `%s' has no type",
GST_PLUGIN_FEATURE_NAME (factory));
return NULL;
}
oclass = GST_ELEMENT_CLASS (g_type_class_ref (factory->type));
if (oclass->elementfactory == NULL) {
GST_DEBUG ("class %s", GST_PLUGIN_FEATURE_NAME (factory));
oclass->elementfactory = factory;
}
/* create an instance of the element */
element = GST_ELEMENT (g_object_new (factory->type, NULL));
g_assert (element != NULL);
g_type_class_unref (oclass);
gst_object_set_name (GST_OBJECT (element), name);
return element;
}
/**
* gst_element_factory_make:
* @factoryname: a named factory to instantiate
* @name: name of new element
*
* Create a new element of the type defined by the given element factory.
* If name is NULL, then the element will receive a guaranteed unique name,
* consisting of the element factory name and a number.
* If name is given, it will be given the name supplied.
*
* Returns: new #GstElement or NULL if unable to create element
*/
GstElement*
gst_element_factory_make (const gchar *factoryname, const gchar *name)
{
GstElementFactory *factory;
GstElement *element;
g_return_val_if_fail (factoryname != NULL, NULL);
GST_LOG ("gstelementfactory: make \"%s\" \"%s\"",
factoryname, GST_STR_NULL (name));
/* gst_plugin_load_element_factory (factoryname); */
factory = gst_element_factory_find (factoryname);
if (factory == NULL) {
GST_INFO ("no such element factory \"%s\"!",
factoryname);
return NULL;
}
element = gst_element_factory_create (factory, name);
if (element == NULL) {
GST_INFO_OBJECT (factory, "couldn't create instance!");
return NULL;
}
return element;
}
void
__gst_element_factory_add_pad_template (GstElementFactory *factory,
GstPadTemplate *templ)
{
g_return_if_fail (factory != NULL);
g_return_if_fail (templ != NULL);
gst_object_ref (GST_OBJECT (templ));
gst_object_sink (GST_OBJECT (templ));
factory->padtemplates = g_list_append (factory->padtemplates, templ);
factory->numpadtemplates++;
}
/**
* gst_element_factory_get_element_type:
* @factory: factory to get managed #GType from
*
* Get the #GType for elements managed by this factory
*
* Returns: the #GType for elements managed by this factory
*/
GType
gst_element_factory_get_element_type (GstElementFactory *factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
return factory->type;
}
/**
* gst_element_factory_get_longname:
* @factory: a #GstElementFactory
*
* Gets the longname for this factory
*
* Returns: the longname
*/
G_CONST_RETURN gchar *
gst_element_factory_get_longname (GstElementFactory *factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return factory->details.longname;
}
/**
* gst_element_factory_get_class:
* @factory: a #GstElementFactory
*
* Gets the class for this factory.
*
* Returns: the class
*/
G_CONST_RETURN gchar *
gst_element_factory_get_klass (GstElementFactory *factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return factory->details.klass;
}
/**
* gst_element_factory_get_description:
* @factory: a #GstElementFactory
*
* Gets the description for this factory.
*
* Returns: the description
*/
G_CONST_RETURN gchar *
gst_element_factory_get_description (GstElementFactory *factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return factory->details.description;
}
/**
* gst_element_factory_get_author:
* @factory: a #GstElementFactory
*
* Gets the author for this factory.
*
* Returns: the author
*/
G_CONST_RETURN gchar *
gst_element_factory_get_author (GstElementFactory *factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return factory->details.author;
}
/**
* gst_element_factory_get_num_padtemplates:
* @factory: a #GstElementFactory
*
* Gets the number of padtemplates in this factory.
*
* Returns: the number of padtemplates
*/
guint
gst_element_factory_get_num_padtemplates (GstElementFactory *factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
return factory->numpadtemplates;
}
/**
* gst_element_factory_get_padtemplates:
* @factory: a #GstElementFactory
*
* Gets the #Glist of padtemplates for this factory.
*
* Returns: the padtemplates
*/
G_CONST_RETURN GList *
gst_element_factory_get_padtemplates (GstElementFactory *factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return factory->padtemplates;
}
/**
* gst_element_factory_can_src_caps :
* @factory: factory to query
* @caps: the caps to check
*
* Checks if the factory can source the given capability.
*
* Returns: true if it can src the capabilities
*/
gboolean
gst_element_factory_can_src_caps (GstElementFactory *factory,
GstCaps *caps)
{
GList *templates;
g_return_val_if_fail(factory != NULL, FALSE);
g_return_val_if_fail(caps != NULL, FALSE);
templates = factory->padtemplates;
while (templates) {
GstPadTemplate *template = (GstPadTemplate *)templates->data;
if (template->direction == GST_PAD_SRC) {
if (gst_caps_is_always_compatible (GST_PAD_TEMPLATE_CAPS (template), caps))
return TRUE;
}
templates = g_list_next (templates);
}
return FALSE;
}
/**
* gst_element_factory_can_sink_caps :
* @factory: factory to query
* @caps: the caps to check
*
* Checks if the factory can sink the given capability.
*
* Returns: true if it can sink the capabilities
*/
gboolean
gst_element_factory_can_sink_caps (GstElementFactory *factory,
GstCaps *caps)
{
GList *templates;
g_return_val_if_fail(factory != NULL, FALSE);
g_return_val_if_fail(caps != NULL, FALSE);
templates = factory->padtemplates;
while (templates) {
GstPadTemplate *template = (GstPadTemplate *)templates->data;
if (template->direction == GST_PAD_SINK) {
if (gst_caps_is_always_compatible (caps, GST_PAD_TEMPLATE_CAPS (template)))
return TRUE;
}
templates = g_list_next (templates);
}
return FALSE;
}
static void
gst_element_factory_unload_thyself (GstPluginFeature *feature)
{
GstElementFactory *factory;
factory = GST_ELEMENT_FACTORY (feature);
if (factory->type) {
g_type_class_unref (g_type_class_peek (factory->type));
factory->type = 0;
}
}